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When the Eyelids Snap Shut at 65 Miles an Hour

A sleep-deprived driver turned Melissa Cullen's life upside down. Ms. Cullen was driving with her father on a country road in Delaware when a car crossed the centerline and crashed directly into her car. Her father was killed, and she was badly injured.

Forced to endure multiple operations, extensive physical therapy, three years of pain and now barely able to see, she had to give up her career as a teacher. The woman whose car struck hers had slept a mere three hours in the 24 hours before the crash and had no idea what she hit or any recollection of the accident, a clear sign that she had fallen asleep at the wheel.

Ms. Cullen is one of the many whose lives, experts say, are jeopardized each day by drivers who cannot stay awake. No one knows for sure whether there has been a rise in drowsy driving, but many transportation safety experts say they are increasingly aware and concerned about the problem.

As a result, researchers are developing a number of novel ways to detect sleepy drivers and warn them that they may fall asleep at the wheel.

But according to estimates by a group of international transportation safety experts, as many as 1.2 million accidents each year in this country -- about 20 percent of the total -- are related to driver fatigue.

Many experts say the problem has grown for a number of reasons.

''One impact of 9/11 has been to put more people on the highways and more stress on society,'' said James E. Hall, a former member of the National Transportation Safety Board. ''People are not flying as much and instead a lot more people are driving long distances.''

He said that he believed that the numbers of drowsy drivers might also be rising because of an increased use of medications that make people drowsy, an aging society, undiagnosed or untreated sleep disorders, jet-lagged drivers, the need to work several jobs to support families and long commutes.

Those factors prompted the National Sleep Foundation to organize a two-day conference, held last week. At the gathering Mr. Hall called drowsy driving ''a silent killer'' that had been difficult to identify and measure and slow to be addressed.

It is not that traffic safety experts are unaware of the toll sleepy driving is taking. The National Highway Traffic Safety Administration and the Federal Motor Carrier Safety Administration, which oversees commercial vehicles, are struggling with ways to curb it.

What are needed, officials agree, are surefire ways to detect drivers who are too tired to drive safely, effective ways to alert them to that fact and -- toughest of all -- means to keep them awake or get them off the road before it is too late.

Also needed is an simple, reliable roadside test to allow officers to assess a driver's alertness before or after an accident.

''There is unfortunately no Breathalyzer for drowsy driving,'' said Col. Gregory Belenky, a doctor in the Army Medical Corps and an expert on sleep deprivation.

Even when drivers know they are sleepy, they may think they can keep driving safely. But in the last century, Americans have shortened their sleep time by an average of 20 percent. In the contest between the will to stay awake and the will to sleep, experts say sleep will always win.

Forty percent of fatal crashes on the New York State Thruway in recent years have been attributed to drowsy, fatigued drivers who drifted off the road, according to traffic experts. Accidents involving sleeping drivers are especially likely to be deadly because they offer no opportunities for braking or efforts to avert collisions.

Various companies have produced more than 100 devices to detect drowsy driving, but none of them have been adequately tested for effectiveness and reliability, said Dr. Mark Rosekind, an expert on measures to counteract fatigue, formerly with the National Aeronautics and Space Administration and now the president of Alertness Solutions.

The company, based in California, works with various groups to help keep drivers awake and alert. A major problem with most of the gadgets, he said, is how people get around them, sometimes unwittingly.

For example, with a device that fits over the ear and sets off an alarm when the driver's head tilts downward, drivers may soon adapt and ''learn'' to fall asleep without tilting their heads. Truckers have been seen on the road sitting straight up with closed eyes and their heads against the backs of their seats.

I.B.M. has been working on a dashboard-mounted device that shoots a jet of cold water at sleepy drivers and, at the same time, rolls down windows, sounds an alarm and switches radio stations. The device detects drowsiness by asking the driver questions and monitoring the responses for speed and clarity. The company hopes to make the device an integral part of new cars within five years.

Still, Mr. Hall said: ''There has traditionally been knee-jerk resistance in the automotive industry to safety changes, and this issue, I'm sure, is no exception. We need advocacy groups to increase awareness and lobby for the necessary changes.''

At last week's conference, the National Summit to Prevent Drowsy Driving, held in Washington at the National Academy of Sciences, Dr. David Dinges, an expert on sleep and body clocks from the University of Pennsylvania School of Medicine, said dozens of claims had been made for devices promoted as ''online monitors of drowsy driving.''

They include a sensor mounted on the roof of the car to detect when the driver's head falls over, a wrist sensor that monitors heart rate, a sleep watch that measures muscle activity, a device worn on the temple that registers eye blinks and electrodes that record brain waves.

The problem, Dr. Dinges said, is finding something that works reliably for everybody, or nearly everybody, in nearly every situation. The head-droop sensor, for example, cannot tell the difference between a driver who is falling asleep or one who is changing the radio dial, glancing at a map or picking up a sandwich.

To date, he said, the device that has proved most reliable in tests is an infrared gadget that detects slowly drooping eyelids, a hallmark of impending sleep. The device, developed at Carnegie Mellon University, pulses two wavelengths of infrared light off the face and bounces them back to a camera on the dashboard, which records a dark face with eyes shining like a cat's and can detect how open the eyes are.

This ''co-pilot'' device, he said, works for nearly everyone, but it too has limits: it does not work as well in bright sunlight or with people wearing certain kinds of lenses. Nor will it work for those rare cases who can fall asleep with their eyes open.

Also being used in some trucks is a tracking system that can detect lane deviations -- when the vehicle has drifted off the tire tracks worn into the roadway -- with a black box that can provide a permanent record should an accident occur, Colonel Belenky said.

''One can imagine all sorts of possibilities for detecting drowsy driving and warning people that they are not fit to drive,'' he said, including a means of measuring increased blood levels of interleukin-6, a substance that correlates well with sleep deprivation.

''Once you have a good monitor of drowsiness, the next issue is how to give this information to the driver,'' Dr. Dinges said. ''Do you use lights, tones, a female voice, release the odor of peppermint or menthol, or what?'' He was not impressed with the idea of squirting ice water. ''And once you sound the alarm, will people continue to drive?'' he wondered, just as many drivers ignore the warning beep of an unbuckled seat belt.

Many major highways now have rumble strips on the right side of the road to awaken drifting drivers. But these cannot prevent a startled sleeping driver from overcompensating and crashing. Nor will they stop someone who drifts to the left or plows straight ahead into a slower vehicle or stopped traffic.

While the best countermeasure to sleepy driving is to pull off the road and nap, Dr. Dinges noted that ''a lot of people don't feel safe doing that.'' In one survey of women who drive, 95 percent said they would not pull into a rest stop to nap. Furthermore, Dr. Dinges said, rest areas are too few and far between on most roads. ''How do we provide frequent safe areas for people to get off the road and sleep, especially those who are driving alone? That is the real public policy issue.''

A recent study of truck stops revealed 24,000 too few slots for trucks, and the number of trucks on the road continues to increase, Dr. Dinges said. At some truck stops, officers routinely waken drivers and tell them to move on to make room for more trucks.